Smoking Status, Nicotine Medication, Vaccination, and COVID-19 Hospital Outcomes: Findings from the COVID EHR Cohort at the University of Wisconsin (CEC-UW) Study

Abstract

Introduction Available evidence is mixed concerning associations between smoking status and COVID-19 clinical outcomes. Effects of nicotine replacement therapy (NRT) and vaccination status on COVID-19 outcomes in smokers are unknown. Methods Electronic health record data from 104 590 COVID-19 patients hospitalized February 1, 2020 to September 30, 2021 in 21 U.S. health systems were analyzed to assess associations of smoking status, in-hospital NRT prescription, and vaccination status with in-hospital death and ICU admission. Results Current (n = 7764) and never smokers (n = 57 454) did not differ on outcomes after adjustment for age, sex, race, ethnicity, insurance, body mass index, and comorbidities. Former (vs never) smokers (n = 33 101) had higher adjusted odds of death (aOR, 1.11; 95% CI, 1.06–1.17) and ICU admission (aOR, 1.07; 95% CI, 1.04–1.11). Among current smokers, NRT prescription was associated with reduced mortality (aOR, 0.64; 95% CI, 0.50–0.82). Vaccination effects were significantly moderated by smoking status; vaccination was more strongly associated with reduced mortality among current (aOR, 0.29; 95% CI, 0.16–0.66) and former smokers (aOR, 0.47; 95% CI, 0.39–0.57) than for never smokers (aOR, 0.67; 95% CI, 0.57, 0.79). Vaccination was associated with reduced ICU admission more strongly among former (aOR, 0.74; 95% CI, 0.66–0.83) than never smokers (aOR, 0.87; 95% CI, 0.79–0.97). Conclusions Former but not current smokers hospitalized with COVID-19 are at higher risk for severe outcomes. SARS-CoV-2 vaccination is associated with better hospital outcomes in COVID-19 patients, especially current and former smokers. NRT during COVID-19 hospitalization may reduce mortality for current smokers. Implications Prior findings regarding associations between smoking and severe COVID-19 disease outcomes have been inconsistent. This large cohort study suggests potential beneficial effects of nicotine replacement therapy on COVID-19 outcomes in current smokers and outsized benefits of SARS-CoV-2 vaccination in current and former smokers. Such findings may influence clinical practice and prevention efforts and motivate additional research that explores mechanisms for these effects.

Risk Factors of Severe COVID-19: A Review of Host, Viral and Environmental Factors

“…However, the frequency and duration of smoking, or time since quitting tobacco use also influence the increased risk posed by this habit. The long-term damaging effects of smoking have been studied by comparing never-smokers to former [ 204 , 789 , 790 , 791 , 792 ] or ever-smokers (former and current smokers combined) [ 124 , 204 , 793 , 794 , 795 ], which consistently showed more severe outcomes (e.g., hospitalization, ICU admission, MV and death) in the latter groups. However, although current smokers compared to (current) non-smokers seem to be more prone to experience severe symptoms and death [ 123 , 794 , 796 , 797 ], when comparing current smokers to never-smokers, some publications reported increased severity [ 204 , 788 , 796 , 798 ], while others no effect [ 791 , 792 , 799 ], and surprisingly, recent cohort studies found lower rates of severe outcomes [ 789 , 790 ] in the smoker group of the study.…”

“…The long-term damaging effects of smoking have been studied by comparing never-smokers to former [ 204 , 789 , 790 , 791 , 792 ] or ever-smokers (former and current smokers combined) [ 124 , 204 , 793 , 794 , 795 ], which consistently showed more severe outcomes (e.g., hospitalization, ICU admission, MV and death) in the latter groups. However, although current smokers compared to (current) non-smokers seem to be more prone to experience severe symptoms and death [ 123 , 794 , 796 , 797 ], when comparing current smokers to never-smokers, some publications reported increased severity [ 204 , 788 , 796 , 798 ], while others no effect [ 791 , 792 , 799 ], and surprisingly, recent cohort studies found lower rates of severe outcomes [ 789 , 790 ] in the smoker group of the study. The short-term effects of tobacco use are harder to measure in clinical settings, but ambiguous results on the effect of current smoking behavior on COVID-19 might imply further physiological and immunological effects that differ from the mechanisms responsible for long-lasting damage in the lungs.…”

Factors associated with 60‐day readmission among inpatients with COVID‐19 at 21 United States health systems

“…Time period of admission was a two‐level variable coded as before COVID‐19 vaccine availability (February 1, 2020 to December 10, 2020) or after vaccine availability (December 11, 2020 to November 30, 2021). In addition, vaccination status before the index admission was analyzed as a three‐level variable (0, 1, or 2 or more doses) 13,24 . Supplementary Text describes the manufacturer of up to the first three doses of vaccination received before the index admission.…”

“…In addition, vaccination status before the index admission was analyzed as a three-level variable (0, 1, or 2 or more doses). 13,24 Supplementary Text S2 describes 17,27 Previous research established threshold effects of area deprivation on hospital readmission as greater than or equal to the 80th percentile. 19 Area SDI was dichotomized into low (below the 80th percentile) and high (greater than or equal to the 80th percentile).…”

COVID‐19 and tobacco products use among US adults, 2021 National Health Interview Survey

“…only used smokeless tobacco. In 2021,13.5% of US adults (estimated 34.1 million) reported having COVID-19 (Table 3), 60.8% (153.9 million) ever tested for COVID-19, 12.5% (31.7 million) ever tested positive for COVID-19, 54.8% (19.6 million) had medium or severe symptoms (vs. no/mild symptoms) associated with COVID-19. Among symptomatic adults, 60.5% (21.5 million) and 58.2% (20.7 EBRAHIMI KALAN ET AL.| 3 of 10 T A B L E 1 T A B L E 1 (Continued) Abbreviations: CI, confidence interval; COVID-19, coronavirus disease 2019; NH, Non-Hispanic; NHIS, National Health Interview Survey.…”